Method and apparatus for continuously casting metal bars, billets, or the like



u y 6, 1957 P. WHITAKER 2,799,065

METHOD AND APPARATUS FOR CONTINUOUSLY CASTING METAL BARS, BILLETS, OR THE LIKE 5 Sheejs-Sheet 1 Filed Sept. 30, 1954 if g Inventor PA 4 l l H/ TA A E A ttorneys July 16, 1957 wHlTAKER 2,799,065

METHOD AND APPARATUS FOR CONTINUOUSLY CASTING METAL BARS, BILLETS, OR THE LIKE Filed Sept. 30, 1954 5 Sheets-Sheet 2 V 28 F/GZ. f

uunu NU lnvenlor P. WHITAKER July 16, 1957 5 Sheets-Sheet 5 Filed Sept. 30, 1954 Inventor I P/ruz I I fl/r/IKER A ttorneys July 16, 1957 P. WHITAKER 2 799,

METHOD AND APPARATUS FOR CONTINUOUSLY CASTING METAL BARS, BILLETS, OR THE LIKE 5 Sheets-Sheet 4 Filed Sept. 30, 1954 Inventor P. WHITAKER 2,799,065

us FOR CONTINUOUSLY CASTING BILLETS, OR THE LIKE July 16, 1957 METHOD AND APPARAT METAL BARS,

5 Sheets-Sheet 5 Filed Sept. 30, 1954 55 nmfcz |:1| own q h: c:1| w

In ventor PA 0/. 1409/77! K51? (.7 Atto neys United States Patent @fitice f fijllGfi Patented July 16, 1957 2,799,065 A METHOD AND APPARATUS FOR CONTINUOUSLY CASTING METAL BARS, BrLL rs, OR THE LIKE Paul Whitaker, near Market Harborough, England, as-

signor to Stewarts & Lloyds Limited, Glasgow, Great Britain, a British company a Application September 30, 1954, Serial No. 459,269

Claims priority, application Great Britain September 30, 1953 7 Claims. (Cl. 2257.2)

This invention relates to a method and apparatus for continuously casting metal bars, billets or the like.

In a usual method of continuous casting the molten metal is fed to the mould solely under the action of gravity, and any tendency for the metal to stick in the mould is overcome by vibrating the the mould.

An object of the present invention is to provide for positive, easily regulatable feeding of .the'molten metal to the mould.

A further object of the present invention is to provide an improved method of preventing sticking of the metal in the mould.

According to the present invention, I provide a method of continuously casting metal bars, billets or the like in which the molten metal is fed to the mould under the action of gas under pressure.

Preferably, the mould is placed in communication with a body of molten metal in a gas-tight container, and gas under pressure is supplied to the surface of the molten metal in the container.

; Preferably, also, a pulsating pressure is superimposed ona steady feed pressure of the gas to tend to prevent sticking of the metal in the mould.

Preferably, also, the metal is fed' through the mould upwardly so that the continuous casting is effected uphill. Further according to the present invention, we provide apparatus for continuously casting metal bars, billets or the like comprising a container adapted for gas-tight enclosure of a body of molten metal, a mould adapted for communication with the body of molten metal in the container, and pressure supply means adapted to supply gas under pressure to the container so that a free surface of the body of molten metal in the container is depressed and feeding of the molten metal through the mould is effected.

The container may be the ladle for the molten metal, or, alternatively, a pressure vessel into which the ladle is passed.

' Preferably variable-speed extraction rollers are provided at the mould exit, and control means are provided to effect simultaneously control of the extraction rollers and the gas supply means so that the speed of the continuous casting is regulated.

Embodiments of the invention will now be described by way of example, with reference to the accompanying drawings, in which:

Fig. 1 illustrates diagrammatically apparatus for the continuous casting of metal billets ina vertically upward direction. v

.Fig. 2 illustrates diagrammatically modified apparatus for the continuous casting of metal billets in a vertically upward direction.

Fig. 3 illustrates diagrammatically further modified apparatus for the continuous casting of metal billets in a vertically upward direction.

Fig. 4 illustrates diagrammatically further modified apparatus for the continuous casting of metal billets in a vertically upward direction; and,

Fig. 5 illustrates diagrammatically apparatus for the continuous casting of metal billets in a horizontal direction.

Referring to Fig. 1 of the drawings, a ladle 1 for the molten metal 2 has a vertical partition 3 spaced from the ladle bottom 4 to define a U-passage through the ladle. Limb 5 of the passage has its upper end open to permit access to the free surface 6 of the molten metal of air or other gas under pressure, and limb 7 of the passage has at its upper end a frusto-conical seat 8 for a correspondingly shaped apertured stopper 9 through which molten metal passes vertically upwards under gas pressure. Preferably such other gas is nitrogen or other inert gas.

The molten metal'within the ladle is subjected to gas pressure in a pressure vessel 10 into which the ladle 1 is conveyed on a wheeled carriage 11 and which is rendered gas-tight with the ladle therein. A vertically arranged mould assembly 12 is mounted over the pressure vessel for vertical reciprocating movement, and has at its lower end a pair of stoppers, one being the ladle stopper 9 which in its downward movement penetrates an aperture 13 in the top of the pressure vessel 10, and the other being the lower end of a refractory entry runner 14 which co-operates with a seating 15 at the aperture to seal the aperture.

Air under pressure is supplied to the pressure vessel through a pair of supply pipes 16 and 17 opem'ng into the top of the vessel, pipe 16 being for static pressure and pipe 17 being for pulsating pressure. The static pressure air is supplied by a pump and the pulsating pressure is superimposed on the steady static pressure by means of a separate pump 60, or a vibrating diaphragm, acting through valve 61.

An optical inspection tube 18 opens into the top of the pressure vessel to enable viewing of the free surface of the molten metal in the ladle, the tube extending angularly to a convenient location for the viewer.

The mould assembly 12 is cylindrical being formed by a vertical series of interconnected cylindrical parts which have aligned through passages for the metal and which consist of a water-jacketed die 19 lubricated as at 20 by a suitable system to facilitate the production of billets of good finish, refractory entry and exit runner blocks 14 and 21, respectively, at the ends of the die, and a water-spray cooling device 22 forming a continuation of the exit block 21 and suitably drained, the device being adapted to cool the cast metal in a controlled manner.

A train of extracting rollers 23 is mounted on the cooling device to engage and withdraw the cast metal 2A issuing from the cooling device, the speed of the rollers being regulatable to vary the extraction speed. The gas pressure is also regulatable, and by simultaneous control of the gas pressure and the extraction rollers, e. g. by suitable electronic control means 24, the speed of the continuous casting operation is readily regulatable,

A heating unit is embedded in the refractory entry runner 14 and is effective on starting of the apparatus, and also to prevent freezing of the metal adjacent to the water-cooled die on stoppage of the apparatus.

A low frequency electronic induction element is em-.

bedded in the refractory exit runner 21, and may be energised so that by controlling the speed: of casting, thecen v oxygen gas cutting unit 27 having provision for striking gas (ferrolene). A manipulating device 28 above the cutting unit extracts the billets 23 from the cutting unit and rotates them through 90 for cross feeding by rollers 29 to a'discharge location.

In use of the apparatus, with the stoppers in upwardly withdrawn position the filled ladle 1 is moved into the pressure vessel through an open end thereof and is located to receive its stopper. The end of the pressure vessel is closed, and the hydraulic jacks 26 are operated to lower the mould assembly 12 so that the stoppers seal the ladle limb and the pressure vessel. Air or gas under predetermined pressure is then passed into the pressure vessel through the supply pipes '16 and 17 and the extraction rollers 23 are rotated at a predetermined speed. The molten metal is forced vertically upwards through the mould assembly by the air pressure on the free surface 6, the superimposed pulsations tending to vibrate the metal in its passage through the die 19 and so prevent sticking of the metal in the die. When the metal in the limb 5 reaches the level of the lower edge of the partition 3 the jacks are operated to lift the stoppers clear, and the pressure vessel is then opened and the ladle removed.

Fig. 2 illustrates a modification in which a removable top cover for pressure vessel 31 carries jacks 32 and mould assembly 33 which slidably engages in a guide tube 34 on the cover. Instead of a ladle stopper, a tubular extension 35 is attached to the entry runner 36. In use, the cover 30 is removed and a filled ladle 37 is deposited in the vessel 31 by crane. The cover is positioned, the extension 35 penetrating below the metal surface 38, and air under pressure is supplied to the vessel from pipes 16 and 17 to depress the free surface of the metal and feed the molten metal vertically upwards through the mould assembly. As the free surface 38 of the metal falls during casting, the jacks are operated to lower the assembly and maintain the extension below the metal surface.

Fig. 3 illustrates a modification in which the pressure vessel is dispensed with and partitioned ladle 39 itself is pressurised. The air supply pipes 16 and 17 and the optical inspection tube 18 penetrate a removable cover plate 40 sealing the opening above the free surface 41 of the molten metal.

Fig. 4 illustrates a modification in which pressure vessel 42 is mounted alongside the vertical mould assembly, and an ordinary ladle 43 deposited by crane through the closable top of the vessel 42 embodies a refractory teeming stopper 44 and bottom nozzle 45. The nozzle 45 extends through the bottom of the vessel .42 and is in communication with die 46 through a U-shaped refractory entry runner 47 having a heating .unit and a suitable drain. A refractory exit runner 48 having a heating unit and a water spray cooling device 49 extend above the die 46. The top cover of the vessel 42.carries the-optical inspection tube 18 and the pipes 16 and '17 for the com pressed air to penetrate the side wall of the vessel. I v

Fig. 5 illustrates a modification in which an ordinary ladle 50, embodying a refractory teeming stopper 51 and bottom nozzle '52, itself constitutes the pressure vessel. The ladle is closed by a removable lid 53 carrying the air supply pipes 16 and 17 and optical inspection tube 18. The ladle is deposited 'by crane on a platform 54 above the level of a horizontally arranged mould assembly 55, and the ladle is in communication with die 56 through an L-shaped refractory entry runner 57 connected to the bottom nozzle 52 and having a suitable drain. Refractory runner 57 has a heating unit. A refractory exit runner 58 having an induction stirring unit, and a water-spray cooling device 59 are provided.

For uphill" casting of steel a gas pressure of 4 to 6 pounds/ square inch per foot length of cast bar is used. Thus a pressure of 60 to lbs/square inch elevates the steel column to a height of approximately 20 feet, where it is engaged by the extracting rolls 23.

In starting up the casting apparatus a starter bar of somewhat smaller diameter than the die can be used. The lower end of this bar is serrated to allow the molten metal to freeze onto the starter bar so permitting almost immediate operation of the extracting rolls.

In operation, a 6 inch square steel bar can be cast at a rate of up to 4 or 5 feet per minute, a 10 inch square bar at up to 2 feet per minute and a 20 inch square bar at up to 1 foot per minute.

What I claim is:

1. A process of continuously casting metal bars, billets or the like, comprising subjecting the molten metal to the combined actions of gas under static pressure and gas under pulsating pressure to feed the metal to and through the mould.

2. A process according to claim 1, in which the metal is fed upwardly through the mould so that continuous casting is effected uphill.

3. A process according to claim 1, in which the cast bar, billet or the like is extracted from the mould by variable speed rollers.

4. A process according to claim 1, in which said gases are substantially inert gases.

5. Apparatus for continuously casting metal bars, billets or the like, comprising a container adapted for gastight enclosure of a body of molten metal, a mould adapted for communication with the body of molten metal in the container, static pressure supply means and pulsating pressure supply means both adapted to supply gas under pressure to the container so that a free surface of the body of molten metal in the container is depressed and feeding of the molten metal through the mould is effected.

6. Apparatus according to claim 5, in which variable speed extraction rollers are provided at the mould exit.

7. Apparatus according to claim 6, in which control means are provided to effect simultaneous control of the extraction rollers and the gas supply means so that the speed of the continuous casting is regulated.

References Cited in'the fileof this patent UNITED STATES PATENTS 262,625 Small Aug. 15, 1882 770,130 Trotz Sept. 13, 1904 944,668 Douteur Dec. 28, 1909 958,613 Forgo May 17, 1910 1,092,937 .Mellen Apr. 14, 1914 1,727,191 Baily Sept. 3, 1929 1,808,370 Munson June 2, 1931 1,856,352 Morris May 3, 1932 2,290,083 Webster July 14, 1942 2,454,961 Booth Nov. 30, 1948 2,530,854 Brennan Nov. 21, 1950 2,569,150 Brennan Sept. 25, 1951 2,578,213 Welblund Dec. 11, 1951 2,623,253 Harrison Dec. 30, 1952 2,667,673 Harrison Feb. 2, 1954 2,682,691 Hatter July6, 1954 

1. A PROCESS FOR CONTINUOUSLY CASTING METAL BARS, BILLEST OR THE LIKE, COMPRISING SUBJECTING THE MOLTEN METAL TO THE COMBINED ACTIONS OF GAS UNDER STATIC PRESSURE AND GAS UNDER PULSATING PRESSURE TO FEED THE METAL TO AND THROUGH THE MOULD. 